Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Black fly - female

Black fly - Female
Brimfield State Forest, Hampden County, Massachusetts, USA
April 26, 2010

Images of this individual: tag all
Black fly - female Black fly - female

Moved from Flies.

I was swarmed by black flies in Brimfield State Forest on Saturday.

I think this is a Prosimulium but I'm not sure. If it's biting you it's female.

What details would you need to see to know for sure?

Is Rs forked or not? The branches can be very close together.

Simulium has basal R cell 1/4 or less wing length and Rs not forked.

Other Simuliini have normal length R cell (~1/3 wing length) and Rs not forked or only forked for a very short distance at the tip.

Prosimuliini have normal length R cell and Rs forked about half its length with branches possibly very close together.

I can almost imagine there being very close branches, but I guess I'll have to try harder for a perfectly dorsal shot next time. At least they're good at holding still!